I experienced this yesterday on dc7700 with lubuntu daily ISO. Alas (yesterday) I didn't find this bug report; thus created a new one (now marked duplicate)...
The noble report can be viewed here - https://bugs.launchpad.net/ubuntu/+source/openbox/+bug/2047931 ** Tags added: noble -- You received this bug notification because you are a member of Canonical's Ubuntu QA, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1882411 Title: lubuntu monitor settings touching screens with gap between Status in lxqt-config package in Ubuntu: New Bug description: This is a Lubuntu groovy (20.10) QA-test install first boot on - dell [optiplex] 755 (c2d-e8300, 8gb, amd/ati radeon rv610/radeon hd2400 pro/xt) As part of post-install checks, I ensure all disk space is utilized..... and finally adjust displays to match the machines setup. It was at this 'adjust displays to match' that this problem occurred. My two displays are positioned "landscape + portrait(left-tilt)." (left display is 1280x1024, right is 1024x768 on this setup) ** Synopsis There is a 'hidden' gap between my displays which shouldn't be there. ** Description The Monitor settings have been adjusted to match (see screen.jpg) with APPLY already pressed. I cannot move the displays closer (Keep.monitors.attached is clicked), yet windows disappear as if a gap exists between displays, and I have to keep dragging mouse to left awhile to get from my.right monitor before it appears in my.left monitor .. the gap correctly portrays to the BLACK dark section seen in screen.jpg ** Expected Results Mouse should move between my.left and my.right monitors as if there is no gap, windows should not disappear (you cannot see left edge of Monitor.Settings window in screen.jpg) in this gap.. ** Upstream filing https://github.com/lxqt/lxqt-config/issues/756 ProblemType: Bug DistroRelease: Ubuntu 20.10 Package: lxqt-session 0.15.0-0ubuntu1 ProcVersionSignature: Ubuntu 5.4.0-26.30-generic 5.4.30 Uname: Linux 5.4.0-26-generic x86_64 ApportVersion: 2.20.11-0ubuntu38 Architecture: amd64 CasperMD5CheckResult: skip CurrentDesktop: LXQt Date: Sun Jun 7 13:38:55 2020 InstallationDate: Installed on 2020-06-07 (0 days ago) InstallationMedia: Lubuntu 20.10 "Groovy Gorilla" - Alpha amd64 (20200606) SourcePackage: lxqt-session UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/lxqt-config/+bug/1882411/+subscriptions -- Mailing list: https://launchpad.net/~canonical-ubuntu-qa Post to : canonical-ubuntu-qa@lists.launchpad.net Unsubscribe : https://launchpad.net/~canonical-ubuntu-qa More help : https://help.launchpad.net/ListHelp